The cross- sectional study was carried out at AIMS Bellur on normal healthy school going children in the age range of 5-16 years of Bellur region involving two schools over a period of 6 months. All children from both schools meeting inclusion criteria were enrolled in the study. Permission was obtained from the relevant school authorities. Children of both sexes in the above age range belonging to the rural areas along with their parents were provided with written information on the intension of the survey and requested a written consent from the parents for the participation of each student in the survey. The students of the higher class were, in addition, given a brief talk on the study intended and obtainedrequired permission. The students from less affluent status (most) where parents literacy was poor, the class teacher has given consent as guardian. A detailed history, followed by a thorough clinical examination was done as per the latest guidelines laid down by the American Thoracic Society [4]. These children were then interviewed to rule out the following.

1. History suggestive of cold or any other respiratory disease within the preceding two weeks.

2. Past history of asthma, allergies or chest injuries.

3. Family history of asthma among first degree relatives.

Finally, all children were selected randomly. Age was taken as completed years as on the school records. The anthropometric measurements were taken were weight and height. Weight was taken without foot wear and with school uniform. The weighing machine was put on an absolutely flat surface and was calibrated before taking measurements. Accuracy of the machine was ± 50 grams. Any fraction of weight thus measured was corrected to the nearest kilogram. Children who were found as malnourished as per the Indian Academy of Paediatrics criteria (All grades ofmalnutrition) were excluded from the study. The height of children was measured using stadiometer without footwear and child standing erect with the heel and back against anthropometric rod. The measured height was then corrected to the nearest centimeter. Throughout the study same balance and stadiometer were used.

A new mini-wright peak flow meter (obtained from clement Clarke International Ltd., U.K) was used as instrument. A single instrument was used throughout the study. The instrument with a graduated scale on the surface and a mouth piece. The graduation starts with 60 L/min to 800 L/min with accuracy of 10 L/min. In about 400 children disposable mouthpieces were used and remaining children The mouthpiece was washed and sterilized for each subject [5].

The nose clips were not worn. Before the test was carried out the purpose and technique of measurement were explained to each child. All children were tested in standing position. After a practical demonstration the subject was asked to take deep breath and then blow out as hard as possible, in a short sharp blast through the mouth piece of peak flow meter. The resulting flow rate was read from the dial on the meter. At least 5 readings were taken after several practice trials and the mean of three highest values was recorded in the proforma. Measurement of flow rate was carried out by single observer, so that inter observer variation was eliminated.

The data was analysed separately for boys and girls with respect to age, weight, height and PEFR for all children and statistical diagrams were prepared The predictions equations for PEFR based on the height alone were determined for both sexes and also regression equations for both groups (Boys & Girls) were determined. All the results were subjected to standard statistical evaluation (SPSS Package in software) and regression equation for PEFR was obtained based on height.

One thousand twenty eight helathy children of both sexes between 5-16 years were analysed for PEFR values. There were 571 boys and 437 girls. The PEFR values increased in linear relation to age weight and height. The mean age of the boys was 10.68 ± 3.45 years, mean height was 138.57 ± 15.82cm and mean weight was 31.23±10.56kg. The mean age of the girls was 10.49 + 3.45 years, mean height was 135.45+ 16.14cm and mean weight was 30.18 + 10.96kg. The mean PEFR were 292.85+ and 255.01+77.80 for boys and girls respectively. [Table/Fig-1 and 2] give the PEFR values in relation to height for boys and girls respectively.

The PEFR values increased in linear relation to age, weight and height. The coefficient of correlation obtained for all the three variables was significant (p<0.001). The highest correlation was obtained between PEFR and height (r=0.8825 for girls, r=0.7624 for boys). The regression equation based on height for both sexes were [Table/Fig-3 and 4].

[Table/Fig-3]:

Pefr for various hieghts with regression equation in boys

[Table/Fig-4]:

Pefr for various heights with regression equation in girls

Boys: PEFR (L/min) = 4.40 × Ht (cm) – 317.42 L/min.

Girls: PEFR (L/min) = 4.25 × Ht (cm) – 321.21, L/min.

A nomogram has been constructed from the linear regression equation by using PEFR as a dependant variable and height as a independent variable since the difference in PEFR between boys and girls at given height (variability) is only 7-8%. Hence we combined the data for the purpose of nomogram. This can be used for quick estimationof PEFR at any given height [Table/Fig-5]. The regression equation in both sexes based on height is:PEFR= 4.41× Ht (cm) – 328.62 L/min.

[Table/Fig-5]:

Pefr for various heights with regression equation in both sex

Assessment of lung functions both qualitatively and quantatively in both healthy and diseased subjects has become important in the field of Respiratory medicine. Measurement of PEFR has gained worldwide importance in clinical practice for evaluation of patients with obstructive and restrictive airway diseases. Particularly following development of simple handy instrument like the miniwright peak flowmeter. In those known to have asthma, such tests are useful in assessing the degree of airway obstruction and the disturbance in gas exchange, in measuring response of the airways obstruction and the disturbance in gas exchange, in measuring response of the airways to inhaled allergens and chemicals or exercise, in assessing the response to therapeutic agents, and in evaluating the long term course of the disease [6,7]. Our aim was to establish normal values of PEFR for healthy rural children of Bellur (Karnataka), as PEFR is a reliable measurement, which can be used routinely and regularly in rural areas for assessment of airway obstruction and prediction formula derived for use in this population [8].

A standardized comparison of predicted PEFR values from the present study for 3 different heights was done with the PEFR values for the same height from 5 previous studies [Table/Fig-6].On comparing our data with previously published values, we found that PEFR meausrements in rural children are comparable with previous studies [Table/Fig-6]. PEFR values increased in linear relation to age, weight and height. Similar to our study results, many other authors have also found a significant positive correlation of PEFR with age, height, and weight, out of which height has been maximally correlated with PEFR [8–16]. It will also be possible to predict PEFR for a given height by calculating it from our equation. We used height for constructing the regression equation for predicting PEFR because it is a convenient measurement and its assessment is accurate, if proper technique is used. Assessment of correct age in rural area in many instances is not possible and accurate weight measurement in field studies may sometimes pose a problem. It has been shown that pulmonary function, especiality lung volume show racial and ethnic differences [17,18]. Within India also, ethnic differences have been shown to account for the variations in the pulmonary functions [17]. Therefore, it is important to establish reference values for this region. The regression equations obtained in the present study can be used to calculate the expected value of PEFR, which can serve as reference value. We would like to state that a data from few villages is not representative of characteristics of a region. Therefore, the findings of the present study should be considered preliminary and call for further studies with a large sample size based on random selection.

In conclusion, this study has generated preliminary reference values for PEFR for rural children of Bellur, India.